DISCLAIMER: PW's dosage information is gathered from users and resources for educational purposes only. It is not a recommendation and should be verified with other sources for accuracy.

Efavirenz (sold by the brand name Sustiva) is an antiretroviral medication used in the treatment and prevention of HIV/AIDS.[1] It is notable for being able to produce psychedelic and hallucinogenic effects despite possessing an extremely novel pharmacological profile and chemical structure not shared with any other psychedelic substance.

Efavirenz was approved for medical use in the United States in 1998.[citation needed] It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system.[2]

Recreational use of efavirenz for its hallucinogenic and dissociative effects has been reported in South Africa. The tablets are crushed and smoked in a mixture known as whoonga and nyaope.[3][4][5]

Chemistry

Unlike most psychedelics, efavirenz is not a tryptamine, phenethylamine or lysergamide. Efavirenz is classified as a benzoxazine and has several different moieties which give it a unique pharmacological profile. On the two position of the benzoxazine ring, efavirenz has a ketone attached. Efavirenz also has a trifluoromethyl group as well as a cyclopropane ring.

Efavirenz is a white to slightly pink crystalline powder with a molecular mass of 315.68 g/mol. It is practically insoluble in water (<10 µg/mL).[citation needed]

Pharmacology

Pharmacologically, efavirenz is primarily classified as a non-nucleotide reverse transcriptase inhibitor, or NNRTI. Reverse transcriptase is an enzyme found in several viral species that is a type of DNA polymerase and nuclease that allows viruses like hepatitis and human immunodeficiency virus to transcribe viral RNA into DNA. Efavirenz is considered a non-nucleotide reverse transcriptase inhibitor because it does not have a structure based off of a nucleotide.

Unlike most non-nucleotide reverse transcriptase inhibitors, efavirenz is also a 5-HT2A partial agonist, similar to LSD. Additionally, efavirenz is a serotonin and dopaminereuptake inhibitor and a vesicular monoamine transporter 2 inhibitor. Efavirenz also acts as a GABAA positive allosteric modulator, similar to benzodiazepines and barbiturates.[6] Efavirenz has a bioavailability of about 40-45% when it is taken on an empty stomach.

Efavirenz is known to cause a false-positive for cannabis on some urine tests.[7]

Subjective effects

The effects listed below are based upon the subjective effects index and personal experiences of PsychonautWikicontributors. The listed effects should be taken with a grain of salt and will rarely (if ever) occur all at once, but heavier doses will increase the chances and are more likely to induce a full range of effects. Likewise, adverse effects become much more likely on higher doses and may include serious injury or death.

Tolerance and addiction potential

Efavirenz is not known to be habit-forming. While developing a tolerance to efavirenz is extremely rare, abusing efavirenz may cause HIV to become resistant to the drug and increase the viral load in patients with HIV.

Dangerous interactions

As efavirenz may cause hepatoxicity at high doses or after chronic use, it is not recommended to take this substance concurrently with other substances that may cause hepatoxicity. Efavirenz is an inducer of the CYP2B6 and CYP3A4 enzymes of the cytochrome P450 system, and as a result may change the metabolism of drugs metabolized by them. Consuming garlic may decrease serum levels of efavirenz.

Efavirenz is a weak serotonin reuptake inhibitor, so it is possible that combining heavy doses of efavirenz and the substances listed below may result in serotonin syndrome.
Combinations with the following substances can cause dangerously high serotonin levels. Serotonin syndrome requires immediate medical attention and can be fatal if left untreated.